SaaS (Software as a Service) is a service to provide a function of software such as an application to a user. By providing utilize service in a user data storage unit to the service on the SaaS, it is possible to gather data of various application that an individual and a corporation use. The user data storage unit has an access restriction function, and an access control based on certification Cookie and a certification token is performed, for example.
In a case that the certification Cookie is used, a server transmits the certification Cookie to a client when the user certification by the client is successful. The client adds the certification Cookie to a service request indicating the access to the user data storage unit and transmits it to the server. The server admits the access to the user data storage unit based on the certification Cookie.